Chronic pain hurts, too. And the makers of the drug duloxetine--commercially known as Cymbalta--argue Cymbalta can help with that, as well.

So Eli Lilly and Co. on Thursday made the case to a Food and Drug Administration advisory committee that its antidepressant, which has been approved for diabetic nerve pain and fibromyalgia, should get the FDA's blessing as a treatment for a wide range of chronic pain conditions, including those caused by osteoarthritis.

The FDA's advisory panel on arthritis drugs responded Thursday with a very qualified yes. It recommended the FDA expand the population of patients to whom Eli Lilly may market Cymbalta to include those with NIH back pain site" href="http://www.ninds.nih.gov/disorders/backpain/detail_backpain.htm" target="_blank">chronic back pain -- defined as back pain persisting for more than three months. But the panel's members advised against allowing Lilly to promote Cymbalta to those with musculoskeletal pain -- such as knee pain resulting from osteoarthritis.

The vote in favor of adding chronic back pain to the uses for which FDA approved Cymbalta was 8 to 5. The vote against adding musculoskeletal pain -- knee pain because of osteoarthritis specifically -- was 9 to 4. If the FDA accepts only the chronic back pain indication for Cymbalta, the number of patients to whom the medication could be marketed would expand immensely. Back pain is the second most common neurological condition in the United States, after headaches, and chronic back pain is the most common cause of job-related disability in the U.S.

Cymbalta is an antidepressant that elevates levels of serotonin and norepinephrine in the brain. Pharmacologists have widely observed that, in addition to lifting mood, the drug effectively blunts the sensation of hurt in patients with persistent inflammation of nerves and overactivity in the regions of the brain that process pain.

Dr. Robert Baker, Lilly's global development leader for psychiatry and pain disorders, said that Cymbalta reduces pain even when it is not accompanied by depression, and he argued that the company had met the FDA's guidelines for demonstrating it is effective for musculoskeletal pain as well. He said the company was encouraged by the panel's willingness to broaden the uses for which Cymbalta can be marketed and expressed optimism that the company will be able to make its case that the medication works for pain that arises from arthritic and other musculoskeletal conditions.